<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>propsData</title>
    <script type="text/javascript" src="../assets/js/vue.js"></script>
</head>
<body>
    <h1>propsData</h1>
    <hr>
    <header></header>

    <script type="text/javascript">
       var header_a = Vue.extend({
         template:`<p>{{message}}--{{a}}</p>`,
         data:function(){
            return {
                message: 'Hello , I am header!'
            }
         },
         props:['a']
       });
   
       new header_a({propsData:{a:12}}).$mount('header');

    </script>
</body>
</html>